Rig for rotary drilling of holes and shafts

ABSTRACT

A rig for rotary drilling, in which a pilot drilling tool is disposed coaxially relative to the drilling string and side drilling tools are radially displaced with respect to the pilot drilling tool, with the side tools rotating freely and partially overlapping the pilot tool drilling tool and disposed above the latter in a body which is rigidly connected to the drilling string.

O Umted States Patent 11 1 1111 3,743,037

Bulakh et al. 1 July 3, 1973 [5 1 RIG FOR ROTARY DRILLING 0F HOLES .323.322 :38: g ve 7/ 23 entice... AND 2.039.551 5/1936 Phipps 175/354 [76] Inventors: Georgy lvanovicll Bulakh, 2,208,530 7/l940 Thompson l75/335 U.S.S.R.

[22] Filed: Apr. 22, 1971 211 Appl.No.: 136520 [521 US. Cl 175/334, 175/391, 175/354 [51] int.Cl 1221b 9/24 [58] Field of Search l75/334, 335, 354, 175/391, 345

[56] References Cited UNITED STATES PATENTS 2,703,698 3/1955 Westerman 175/334 l 1 E I 1 1 f:

1 E a I i i k I l l I l Oktyabrsky prospekt, 365, kv. 29, Ljubertsy Moskovskoi Oblasti; Vladimir Alexnndrovich Vysotsky, naberezhnaya Tarasa Shevchenko, l/2, kv. 270, Moscow, both of France l75/334 Primary Examiner-James A. Leppink Assistant Examiner--Richard E. Favreau Attorney-Holman & Stern ABSTRACT A rig for rotary drilling, in which a pilot drilling tool is disposed coaxially relative to the drilling string and side drilling tools are radially displaced with respect to the pilot drilling tool, with the side tools rotating freely and partially overlapping the pilot tool drilling tool and disposed above the latter in a body which is rigidly connected to the drilling string.

2 Claims, 4 Drawing Figures RIG FOR ROTARY DRILLING OF HOLES AND SHAFTS BACKGROUND OF THE INVENTION The present invention relates to rigs for the rotary drilling of holes and shafts, particularlyfor holes from 300 to 4,200 mm and more in diameter. This does not exclude the possibility of using the present invention for rigs for the rotary drilling of holes and shafts of smaller and greater diameters.

PRIOR ART Already known in the art, for instance, from GFR Patent No. 881,484, of June 29, 1953, C1. a, 14/20, are rigs for rotary drilling of holes and shafts, comprising a drilling stringwith a pilot drilling tool disposed coaxially therewith, and a body mounted on the drilling string by means of bearings and carrying side shafts radially displaced relative to the pilot drilling tool. The side shafts are mounted by one of their end portions in bearings in the body and have at the other end portions which protrude from the body, with a drilling tool on such protruding portion disposed above the pilot drilling tool and partially overlapping the the pilot tool in such a manner that in the course of drilling, there takes place a stepwise destruction of the bottom hole along its whole cross section, with the side shafts being imparted rotation by the drilling string through chain drives. With the body connected to the drilling string by means of bearings, there can no longer be effected any control over the rotation of the body since, with the drilling tools somewhat penetrated into the rock, or in case there is an obstacle (unevennes, large pieces of rock, etc.) in the bottom hole, the resistance offered to the transfer motion of the side drilling tools may exceed the torque arising on the body due to the reaction forces of the bottom, and the body will come to a stop, thus resulting in axial depending of the side drilling tool and discontinuation of the process of the hole sinking, although the pilot and side drilling tools will continue to rotate. Besides, the fact that each side shaft is provided with a chain drive which make the operation of the drilling tools dependent on one another, results in a more complicated design of the rig and less reliability in its operation.

It is an object of the present invention to eliminate the above-mentioned disadvantages.

SUMMARY OF THE INVENTION The present invention has as its object the provision of such a rig that, due to a different arrangement of the body and side shafts, is sufficiently reliable and more efficient in operation, and simpler to manufacture.

This object is accomplished in that in a rig according to the present invention, the body is rigidly connected with the drilling string, and the side shafts are mounted in the body loosely, whereby the side shafts can rotate about their axes irrespective of one another.

As a result of the present invention, there is provided a rig for drilling holes and shafts, which, as compared to conventional rigs, possesses a number of advantages.

Due to the fact that the body is rigidly connected with the drilling string and the side shafts are mounted loosely, the present rig operates irrespective of the value of deepening of the drilling tools into the rock and the state of the bottom hole thereby making it possible to vary within a wide range the drilling practices, as well as to ream the sections which were previously drilled. All this raises the efficiency of drilling and makes the operation more economical.

The following description of exemplary embodiments of the present invention is given with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a general view of the rig for drilling holes and shafts, with one row of side drilling tools, according to the invention, comma the view being partly in elevation and partly in section;

FIG. 2 shows a general view in elevation of the rig for drilling holes and shafts of a large diameter, with two rows of side drilling tools, according to the invention;

FIG. 3 is a section taken along line III-III of FIG. 2, the view looking in the direction of the arrows; and

FIG. 4 is a section taken along line lV--IV of FIG. 2, the view looking in the direction of the arrows.

DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1, a rig for drilling holes and shafts comprises a drilling string 1, a body 2 with a central pipe 3, shafts 4 with bearings 5, weighting loads 6, a nut 7, a centrally disposed pilot drilling tool 8 and side drilling tools 9. The body 2 is rigidly connected with the drilling string 1 by means of the central pipe 3 which is either welded to the body, made integral therewith, or is connected thereto by any other method. Mounted on the body 2 in the bearings 5 by one of their end portions are the side shafts 4, so that each of the shafts 4 can rotate about its axis freely and independently of the other shafts.

Secured to the end portions of the shafts 4 protruding from the body 2, are drilling tools 9 mounted at one end the same level and radially displaced relative to the pilot drilling tool 8 which is arranged coaxially with respect to the drilling string 1, with the side drilling tools 9 partially overlapping the pilot drilling tool 8. Both single-cone, spherical or tapered, three-cone, multicone, and three-disc multi-disc, hits as well as blade or diamond drill bits and heads can be used as the drilling tools 8 and 9.

The present rig makes it possible to carry out diamond drilling of holes, for which purpose a diamond drill bit, for example, 212-214 mm in diameter can be used as a pilot drilling tool, and heads covered with diamonds as the side tools.

To drill holes of larger diameters equalling, for instance, 4200 mm, the rig may be constructed as shown in FIGS. 2,3, and 4, and comprise a drilling string la, a pilot drilling tool 10 of, for instance, a cutting type arranged centrally, and a body incorporating a central pipe 11 provided with a support plate 12 and three cross pieces l3, l4 and 15 carrying side shafts l6, l7 and 18, respectively, with tools (bits) 19, 20 and 21 radially displaced relative to the pilot drilling tool 10 which is disposed coaxially to the drilling string 1a; The side shafts l6, l7 and 18 are installed in the cross pieces 13, 14 and 15 in a manner similar to the shafts 4. The cross pieces l3, l4 and 15 are disposed one above another and are tightened to the support plate 12 by bolts 22 to form a monolithic system. The side tools are radially displaced from the tool 10 over various distances so that the tools 19 of the lower cross piece 13 partially overlap the pilot drilling tool 10; the tools 20 of the cross piece 14 partially overlap the tools 19, and the tools 21 of the cross piece partially overlap the tools 20. Thus, a stepwise destruction of the bottom hole over the entire cross section is provided.

This embodiment of the rig makes it possible to form a hole of a predetermined diameter either immediately, or by way of preliminary drilling of the hole by this rig with only one cross piece 13 (without using the cross pieces 14 and 15), to be followed by its reaming by means of the same rig using this time also the cross pieces 14 and 15.

The rig shown in FIG. 1 functions as follows:

The rig is rotated by means of the drilling string 1, and a pilot hole is drilled by the central tool 8. With the body 2 of the rig rigidly connected to the drilling string 1, the tools 9 connected to the side shafts 4 are imparted a transfer motion about the axis of the rig by the rotation of the drilling string 1. As the shafts 4 carrying the tools 9 can rotate freely, each of the side tools is imparted rotation independently of one another about its axis by contact with the bottom hole while drilling the rock along an annular area around the bore formed by the pilot tool.

When effecting drilling by means of the rig of the present invention, it is possible to use both direct and reverse circulation. When using the reverse circulation,

the cuttings are delivered into the drilling string through openings (not shown in the drawing) provided in the pilot tool.

The rig shown in FIGS. 2, 3 and 4 operates similarly and, therefore, its operation is not described in detail.

We claim:

1. A rig for the rotary drilling of holes and shafts, comprising a drilling string; a pilot drilling tool arranged coaxially relative to said drilling string; a body for said rig rigidly connected to said drilling string, side shafts carried by said body and being displaced radially relative to said pilot drilling tool; said side shafts having opposite end portions, bearings in said body in which one of the end portions of the side shafts is mounted to allow the side shafts to be capable of rotating freely about their axes, other end portions of the side shafts protruding from the body; and drilling tools secured to the protruding end portions of said side shafts and being disposed above said pilot drilling tool so that said side drilling tools partially overlap the pilot drilling tool.

2. The rig as claimed in claim 1 including a plurality of vertically spaced sets of side drilling tools, with the uppermost set of side tools overlapping the side drilling tools of the set therebelow. 

1. A rig for the rotary drilling of holes and shafts, comprising a drilling string; a pilot drilling tool arranged coaxially relative to said drilling string; a body for said rig rigidly connected to said drilling string, side shafts carried by said body and being displaced radially relative to said pilot drilling tool; said side shafts having opposite end portions, bearings in said body in which one of the end portions of the side shafts is mounted to allow the side shafts to be capable of rotating freely about their axes, other end portions of the side shafts protruding from the body; and drilling tools secured to the protruding end portions of said side shafts and being disposed above said pilot drilling tool so that said side drilling tools partially overlap the pilot drilling tool.
 2. The rig as claimed in claim 1 including a plurality of vertically spaced sets of side drilling tools, with the uppermost set of side tools overlapping the side drilling tools of the set therebelow. 